276 



INSECTS INJURIOUS TO STAPLE CROPS. 



sion, if perfect, forms a cream which thickens upon 

 cooling, and should adhere without oiliness to the surface 

 of glass. Dilute one part of the emulsion with 25 parts 

 of water." Kerosene and water mechanically mixed 

 ('^ Kerowater ") would doubtless be equally effective 

 applied at a strength of 15 or 20 per cent. 



Fig. 159. — The Hop Plant-louse, male — enlarged. (After Riley, 



U. S. Dept. Agr.) 



Fish -oil or whale-oil soap used at the rate of one pound 

 to eight gallons of water will prove an effective spray 

 against the lice. It can be purchased at from 3 to 5 cents 

 per pound. 



The Hop-vine Snout-moth {Hypena Immnli Harr.). 



The larvae of the Hop-vine Snout-moth sometimes 

 become very formidable pests in the hop-field, appearing 



